As slappy said it will work fine and most (but not all) can run a itunes server, theres tones on the market that do all sort of tricks so depends on what else u want to do with it ie they can run torrents or newsgroup dl's with the need for a comp, php/sql ot ftp servers, streaming for PS3 xbox360 or other media devices etc etc...and then hard drive connection is another thing to check out ie SATA USB and IDE, oh and capacity
Id check what features u want/need it will narrow it down a bit
Heres 2 that been recommended to me by people, but not had the chance to play with around with em so id do research 1st but u can get an idea of features
Friend has the model b4 this one but its hard to find this is the new version.
http://www.novatech.co.uk/novatech/specpage.html?SYN-DS109J
And this one is one a friend has as well, not seen or used it but he says its ok lol
http://www.scan.co.uk/Products/1Tb-Buffalo-LS-CH10TL-Linkstation-Live-with-Gigabit-Ethernet-Bit-Torrent-DLNA-Certified
Oh btw the 1st one dosent come with a hard drive i dont think.